Zwick is directing from a script he co-wrote with Marshall Herskovitz. Legendary Pictures chairman Thomas Tull and Max Brooks conceived the story, which explores the mystery behind the construction of The Great Wall of China.

Pic will be produced by Zwick, Herskovitz, Tull and Legendary's Jon Jashni, along with Atlas Entertainment's Alex Gartner and Charles Roven. "Great Wall" will be the first film from the Legendary East banner that was launched in June by Tull and Asian investors, with the goal of producing one or two event films a year.

Walker had been slated to star opposite Bradley Cooper in Alex Proyas' "Paradise Lost," but Legendary pulled the plug on that pic, allowing Walker to take a lead role in Stephen Frears' HBO telepic "Muhammad Ali's Greatest Fight." Thesp starred in "Bloody, Bloody Andrew Jackson" on Broadway before landing the title role in Timur Bekmambetov's "Abraham Lincoln: Vampire Hunter," which 20th Century Fox opens June 22.